Test fixture for hydraulic cushion device



Nov. 12, 1968 T. 1.. ROESEL TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE 4Sheets-Sheet 1 g V mm wm S 1 *5 S 8 mm mm E E m 2w f 4 mm 1 x m 1 r/ T LLL; m mm milLrllFlw K f alli- Filed Jan. 23, 1967 INVENTOR I THOMAS L.ROESEL ayfw x? W) ATT'Y Nov. 12, 1968 T. ROESEL TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE 4 Sheets-Sheet 2 INVENTOR vw mw mm mm Filed Jan. 23,1967 THOMAS L. ROESEL ATT'Y.

T. L. ROESEL TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE Nov. 12, 1968Filed Jan. 2s, 1967 4 Sheets-Sheet IN VENTOR THOMAS L. ROESEL ATT'Y.

Nov. 12, 1968 T. 1.. ROESEL TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE 4Sheets-Sheet 4 Filed Jan. 23, 1967 INVENTOR THOMAS L. ROESEL ATT'Y.

United States Patent 3,410,131 TEST FIXTURE FOR HYDRAULIC CUSHION DEVICEThomas L. Roesel, Lansing, Ill., assignor to Pullman Incorporated,Chicago, Ill., a corporation of Delaware Filed Jan. 23, 1967, Ser. No.611,154 3 Claims. (Cl. 73-11) ABSTRACT OF THE DISCLOSURE A text fixturefor testing operation of an extendable and contractable hydrauliccushioning unit of the type disclosed in US. Patent 3,003,436 which isused in cushion underframe railway vehicles to minimize lading damage.The test fixture includes means for moving the cushion unit against astop from an extended to a contracted position and for releasing thestop so that a return spring of the cushion device is operative toreturn the device to the extended position.

Summary of the invention The cushion device or unit of the type to betested by the test fixture of the present invention includes a hydraulicfluid filled cylinder in which there is mounted for reciprocation fluiddisplacement means in the form of a piston assembly. The cushion unit isadapted to be disposed for inter-action between the underframe andsliding sil'l of a cushion underframe railway vehicle. Upon impact tothe couplers carried by the sliding sill, the cushion unit travels froman extended position to a contracted position during which travel aportion of the impact of energy is absorbed or dissipated to providelading protection to the lading carried on the railway vehicle. Afterthe impact has been dissipated a return spring disposed between thepiston assembly and the hydraulic fluid filled assembly is operative toreturn the components of the unit to the extended position.

The cushion test fixture of the present invention is arranged to receivethe cushion unit in its extended position. Means are provided forcontracting the cushion unit components from their extended to acontracted position to simulate to some extent the condition occurringin the railway car in which it is adapted to be installed. To check thefunctioning of the cushion unit under its severest conditions there isprovided a means on the test fixture for contracting the cushion andthereafter releasing the cushion components from the latter position.The means for releasing the cushion are required to be constructed andarranged to achieve a rapid release so that the spring of the cushionunit is operative to return the components to the original extendedposition as rapidly as possible. Under these conditions of test there issimulated as closely as possible the condition occurring when thesliding sill is bound within the stationary sill and thereby holding thecushion unit in contracted position until the binding cause is overcomeand the return spring is operative to rapidly return the components tothe original extended position. During such rapid return severe stressesare imposed on the various components of the cushioning device and atthe same time extreme hydraulic flow conditions occur within thehydraulic unit which also may create a problem area in connection with aflexible boot reservoir associated with the cushion unit.

Description of the invention In the drawings:

FIG. 1 is a fragmentary top plan view of the test fixture embodying theprinciples of the present invention with some of the parts broken awayto show underlying details of structure and the position.

3,410,131 Patented Nov. 12, 1968 FIG. 2 is a side elevational view ofthe cushion test taken generally along the lines 22 of FIG. 1.

FIG. 3 is a fragmentary top plan view of the cushion test fixture withthe cover removed and showing the cushion unit disposed therein with thecomponents thereof positioned after the fixture stop has been released.

FIG. 4 is a cross sectional view taken generally along the lines 4-4 ofFIG. 1.

FIG. 5 is a cross sectional view taken generally along the lines 5-5 ofFIG. 1.

FIG. 6 is a perspective view partially in section shoW- ing thecushioning device adapted to be tested in the text fixture illustratedin FIGS. 1 to 5 and showing the components of the cushioning device intheir extended position, and

FIG. 7 is a view similar to FIG. 6 but showing the components of thecushioning device in the contracted position.

Referring now to the drawings, in particular FIGS. 6 and 7 there isshown the cushioning device or unit C adapted to be tested in the testfixture 10 illustrated in FIGS. 1 to 5. The cushioning device is of thetype as heretofore mentioned which is used in cushion underframe railwayvehicles for minimizing the lading damage carried on the railwayvehicle. The cushioning device comprises generally a hydraulic filledcylinder 11 in which there is reciprocally disposed for relative travela piston head assembly 12 which is operative to displace fluid from oneside of a piston head 13 to the other side thereof. Connecting a pistonrod 14 to an intermediate cylinder head 16 mounted in the cylinder 11 isa flexible boot 17 which receives the hydraulic fluid displaced by thepiston rod during movement of the piston head assembly 12 from theextended contracted position as shown in FIGS. 6 and 7 respectively. Theflow of the hydraulic fluid is metered from one side of the piston head13 to the other by means of a metering pin 18 which extends through anorifice 19 provided in the piston head 13 and into the bore 21 of thehollow piston rod 14.

During relative movement of the piston head assembly 12 and the cylinder11, fluid is displaced from a chamber 23 to a chamber 24 by way of themetered orifice 19 to impart a substantially constant force travelcharacteristics to the cushion unit C. Movement of the cylinder 11 andpiston assembly 12 continues until the device reaches its fullycontracted position as shown in FIG. 7. After the impact causing therelative movement has been dissipated a spring 26 disposed between abase plate 27 fixed to the cylinder 11 and a base plate 28 fixed to theend of the piston rod 22 is operative to return the unit C back to itsneutral or extended position. During the contraction the hydraulic fluidis also introduced into the flexible boot 17 by way of an opening 29provided in the intermediate cylinder head 16 through which the pistonrod 22 extends.

During the travel of the cushioning device C from its extended to itscontracted position the hydraulic fluid displaced by the piston rod isintroduced into the flexible boot 17 causing the latter to expand. Whenthe cushioning unit returns to its fully extended position the expandedboot 17 forces the fluid to return into the cylinder chambers 24 and 25.However when the return of the cushioning unit is rapid as occurs when asliding sill is binding to hold the cushioning unit C in its contractedposition within the underframe of a railway vehicle and an impact occursto release the binding condition, the return spring and the force of theimpact causes a rapid return. Under these conditions the fluid flow maybe such that the boot tends to bulge outwardly under the force of thehydraulic fluid and under some circumstances it may cause the boot torupture in the event an impact is applied in the opposite directionbefore the unit C returns to its neutral or extended position.

7 Referring now to FIGS. 1 to 5 illustrating the test flxture the lattercomprises generally a base 31 formed by suitable channels and the like.Supported on the base 31 are a pair of transversely spaced channels 32having upper and lower flanges 33 and 34, respectively, extendingoutwardly from side webs 36. Fixed across the bottom flanges 34 is abottom plate 37 which defines with the side webs 36 an elongated trough38. Fixed to each of the ends of the trough 37 are channels 39. Spacedinwardly from one end of the fixture 10 is a plate 41 to which there isfixed a clevis 42 to which there is pivotally connected one end of a twoway hydraulic piston unit 44, including a cylinder 46 within which thereis reciprocably mounted a piston head 47 having connected thereto pistonrod 48 extending through the other end of the cylinder 46. The outer endof the piston rod 48 is pivotally connected to a clevis bracket 49 fixedto a base plate retainer means 51 into which one of the base plates 27of the cushioning device C is adapted to be inserted.

I The base plate retainer means includes a back plate 52 extendingtransversely of the trough 38 and side plates 53 having inwardlydisposed flanges 54 forming a cradle into which the base plate 27 isinserted. The side plates are formed with grooves which receive guidebars 57 fixed to the side webs 36 for guiding the base plate retainingmeans of lengthwise movement. Lengthwise actuation of the base plateretainer is achieved by actuation of the two way hydraulic cylinder unit44 by means of a hydraulic motor (not shown).

Spaced inwardly from the end of the plate is a stop arrangement 57 forrestraining opposite cushioning device stop plate 28 against alengthwise movement within the trough 38. The stop arrangement 57 asshown, includes a pair of transversely spaced drum members 5858 eachincluding opposite cylindrical faces 59 and. opposite chord surfaces 61.Each of the drum like members has extending from the upper and lowerbases 62 and 63 thereof shafts 64 and 65 of which the upper shaft 64 isjournal d in a top cover plate 66 extending between the upper flanges 33of the side channels 32. The lower shaft 65 extends through an opening67 in a bottom plate 68 which is similarly fixed to the lower flanges 34of the side channels 32. To reinforce the upper and lower plates 66 and68 there may be provided side plate reinforcing means 69 as shown inparticular in FIG. 1.

Connected to the lower ends of each of the shafts 65 are toggle arms 71of a toggle linkage 72 which is employed to rotate the barrel stopmembers 58 as more fully to be explained hereinafter. The toggle arms 71at one end are each connected to the respective shaft by way of a bolt73 so that upon turning movement of the toggle arm the barrel stopmembers 58 are each rotated.

Connected to the other end of each of the toggle arms 71 by means ofpivot studs 75 are toggle levers 7474 which are connected at theiropposite ends to a common pivot stud 76 carried by a clevis bracket 77fixed to one end of a piston rod 78 of a two-way hydraulic piston unit79, which is also connected to a suitable source of hydraulic fluidunder pressure.

Spaced lengthwise from the barrel stop members 58 is a second stop plate81 against which the cushion unit base plate 28 abuts when the barrelstop members are turned from a position in which the cylindrical faces59 lie in the path of movement of the cushion base plate 27 to aposition wherein the chord surfaces 61 lie parallel to the plate 28permitting the latter to move lengthwise. The second stop plate 81comprises essentially a plate 82 intermediate the sides of which thereis fixed a longitudinally extending plate 83 which abuts against and isflxed to another plate 84. On the outer face of the Plate 82 there maybe aflixed a rubber cushioning assembly 85 comprising a pair of rubberpads 86 between which there is sandwiched a metallic separating plate87. The rubber cushioning assembly 85 serves to prevent metal to metalimpact. Under some circumstances it may be desirable 3,410,131 I is tofurther cushion the shock of impact which results when the base plate 28of the cushion device'Ciabuts against the second stop plate 85. To thisend there is provided a spring cage assembly 86 comprising a pair ofhelical springs 87 which are carried in a housing 88. The housing 88 isdisposed between the. plate 84 and plate 90'. Limiting movement of thespring cage assembly 86 are stop pins 89 which ride within elongateslots 91: In this connection it is to be noted that the stopplateassembly 81 is movable lengthwise of the trough'38'on guide strips 92,so that upon impact thereto the plate 84 engages the housing 86 to movethe latter againsttheforce of the springs 87. Such compression islimited by the length of the slots 91.

Covering the section into which the cushioning device C is adapted to beinserted is a hinged cover plate 93 to the upper side of which there isfastened lengthwise spaced hinge arms 94 which extend beyond the sidechannels 32. Hingedly connecting each of the arms 94 tonne of the sidechannels 32. is a pivot pin 96 which is carried by a pair of outwardlyprojecting arms 97 fixed to the side web 36. At the other end the arms94 are, provided with slots 98 which receive locking pins 99pivotally-carried by a pair of upstanding arms 101 affixed to theopposite side channel 32.

In use, the cushion device is inserted into the trough 38 with one ofthe base plates 27 disposed within the lengthwise movable base plateretaining means 51 connected to the two way hydraulic cylinder unit 44'.The opposite base plate 28 abuts against the cylindrical faces' 59 ofthe barrel stop members 57. Thereafter the cylinder unit 44 is actuatedso that the piston rod 48 connected'to the plate retainer means 51 movesoutwardly, thereby to contract the cushion device against the force ofthe return spring 26 to the position as shown in FIG. 3. When thecushion device C has been completely contracted to the position shown inFIG. 3 the hydraulic fluid is displaced as described heretofore inconnection with the general descrip tion of the hydraulic cushion unitC.

Thereafter, to test the cushioning device C in a manner similar to theconditions which occur in operation in 'a cushion underframe railwayvehicle, the toggle linkage 72 is actuated by way of the cylinder unit79 so as to move the barrel stop members 57 out of the path of movementof the cushion base plate 23, whereupon the cushioning unit returnspring 26 is effected to move the piston head assembly 12 and thecylinder 11 outwardly relative to each other until the base plate 28abuts against the cushion pads 86 of the stop plate 82. It is to benoted that when the circular stop faces 59 are in contact with the baseplate 28 to function as a stop surface that there is merely linearcontact therewith. Thus, the force of the contracted spring 26 istransmitted radially to the center or pivot connection of the barrelstop 57. Under this condition no forces are imposed on the togglelinkage. No radial force is axially transmitted outwardly through-thetoggle arms 71 to the pivot studs to cause further angular outwardmovement of the levers 74 about the common pivot stud 76. In this mannerthe barrels do not tend to rotate and receive the full force exerted bythe cushioning unit C and thereby prevent inadvertent release of thelatter from the contracted position.

To release the cushion unit C from the contracted position it is to benoted that the barrels are rotated so that the two-way cylinder isoperated so that the toggle linkage 71 assumes the position shownin'FIG. 3,*in which position the barrel stops 57 are turned sothat thesector faces lie substantially parallel to the sides of the channelpermitting a free and uninterrupted release of the cushioning unit tothe extended position toward the second stop plate 81. p I

After the above described test procedure has been completed the cushionunit C is inspected to determine whether the components have functionedproperly oihave failed. i

I claim:

1. A test fixture for testing a hydraulic cushioning unit deviceincluding a fluid filled cylinder, a fluid displacement means mountedfor relative reciprocation Within said cylinder for displacing saidhydraulic fluid therein to dissipate impact energy during contractionfrom an extended position, a flexible boot reservoir communicating withsaid cylinder for receiving a portion of said hydraulic fluid displacedduring relative reciprocation, a first base plate fixed to said fluiddisplacement means, a second base plate fixed to said cylinder in spacedlengthwise relationship to said first base plate and spring meansdisposed between said first and second base plates for returning saidcushioning unit from a contracted to extended position, said testfixture comprising a trough-like support, base plate retainer meansmounted for lengthwise movement in said support and adapted to receiveone of said first or second cushioning unit base plates, a first stopmeans mounted on said trough-like support spaced lengthwise from saidbase plate retainer and adapted to engage the other of said cushion unitfirst and second base plates, said stop means comprising a pair oftransversely spaced barrel members mounted for turning movement about avertical axis and each having a pair of opposed cylindrical surfaces anda pair of opposed planar sector surfaces, means for turning said barrelmembers to a position in which one of said cylindrical surfaces isadapted to be engaged by the edges of said other of said base plates andto a position in which said sector surfaces lie in a plane clear of saidbase plate, means for moving said base plate retainer means toward saidfirst stop means so as to contract said cushioning unit, a second stopmeans spaced from said barrel members extending transversely across saidtrough structure and adapted to be engaged by said other base plate whensaid barrel members are rotated to position in which said sectorsurfaces lie in a plane clear thereof and said cushioning unit springmeans is 0perative to extend said cushioning unit.

2. The invention as defined in claim 1 wherein said means for turningsaid barrel members includes .a toggle linkage, and power means foractuating said toggle linkage.

3. The invention as defined in claim 2 wherein said toggle linkageincludes toggle arms which radially receive the force exerted by thecontacted cushioning device when said cylindrical surfaces are engagedby said other of said base plates.

References (Iited UNITED STATES PATENTS 7/1938 De Port 7311 X 9/1964Posse et al. 73-11

